• A Novel Process-Reaction Curve Method for Tuning PID Controllers 

      Dalen, Christer; Di Ruscio, David Luigi (Journal article; Peer reviewed, 2018)
      A novel process-reaction curve method for tuning PID controllers for (possible) higher order processes/models is presented. The proposed method is similar to the Ziegler-Nichols process reaction curve method, viz. only the ...
    • A Semi-Heuristic Process-Reaction Curve PID Controller Tuning Method 

      Dalen, Christer; Di Ruscio, David Luigi (Journal article; Peer reviewed, 2018)
      A simple semi-heuristic method for designing PID controllers for time constant models are shown to be close to optimal. A Process-Reaction Curve method is proposed, composed by a method for approximating stable time constant ...
    • Dynamic model adaptation to an anaerobicdigestion reactor of a water resource recoveryfacility 

      Attar, Shadi; Haugen, Finn (Journal article; Peer reviewed, 2019)
      This study deals with model adaptation of the AM2 model to an anaerobic digestion reactor of a water resource recovery facility, namely a 6000m3 reactor at VEAS WWRF, the largest of Norway. The model is based on the mass ...
    • Estimating uncertainty of model parameters obtained using numerical optimisation 

      Brastein, Ole Magnus; Lie, Bernt; Pfeiffer, Carlos Fernando; Skeie, Nils-Olav (Peer reviewed; Journal article, 2019)
      Obtaining accurate models that can predict the behaviour of dynamic systems is important for a variety of applications. Often, models contain parameters that are difficult to calculate from system descriptions. Hence, ...
    • Model based flow measurement using venturi umes for return flow during drilling 

      Pirir, Ivan; Jinasena, Asanthi; Sharma, Roshan (Journal article; Peer reviewed, 2017)
      In an oil well drilling operation, a proper knowledge of the return fluid flowrate is necessary both for the stabilization of the bottom hole pressure of the well and also as a primary indication of a kick or loss. In ...
    • Modeling and Analysis of Fluid Flow through A Non-Prismatic Open Channel with Application to Drilling 

      Jinasena, Asanthi; Ghaderi, Ali; Sharma, Roshan (Journal article; Peer reviewed, 2018)
      This paper presents the development and validation of a simplified dynamic model of a Venturi channel. The existing dynamic models on open channels are based on the open channel flow principles, which are the shallow water ...
    • Nonlinear observer for hydropower system 

      Vytvytskyi, Liubomyr; Sharma, Roshan; Lie, Bernt (Peer reviewed; Journal article, 2019)
      Estimation of unmeasured states plays an essential role in the design of control systems as well as for monitoring of hydropower plants. The standard Kalman filter gives the optimum state estimates for linear systems. ...
    • On closed loop transient response system identification 

      Dalen, Christer; Ruscio, David Luigi Di (Journal article; Peer reviewed, 2016)
      Some methods for transient closed loop step response system identification presented in the literature are reviewed. Interestingly some errors in a method published in the early 80’s where propagated into a recently published ...
    • PD/PID controller tuning based on model approximations: Model reduction of some unstable and higher order nonlinear models 

      Dalen, Christer; Di Ruscio, David Luigi (Journal article; Peer reviewed, 2017)
      A model reduction technique based on optimization theory is presented, where a possible higher order system/model is approximated with an unstable DIPTD model by using only step response data. The DIPTD model is used to ...
    • Quantitative genetics state-space modeling of phenotypic plasticity and evolution 

      Ergon, Rolf Otto Torbjørn (Peer reviewed; Journal article, 2019)
      Living organisms adapt to changes in environment by phenotypic plasticity and evolution by natural selection (or they migrate). At detailed genetic levels these phenomena are complicated, and quantitative genetics attempts ...
    • Structural observability analysis and EKF based parameter estimation of building heating models 

      Perera, Degurunnehalage Wathsala U.; Perera, M. Anushka S.; Pfeiffer, Carlos Fernando; Skeie, Nils-Olav (Journal article; Peer reviewed, 2016)
      Research for enhanced energy-efficient buildings has been given much recognition in the recent years owing to their high energy consumptions. Increasing energy needs can be precisely controlled by practicing advanced ...
    • Third Order Reconstruction of the KP Scheme for Model of River Tinneselva 

      Dissanayake, Susantha; Sharma, Roshan; Lie, Bernt (Journal article; Peer reviewed, 2017)
      The Saint-Venant equation/Shallow Water Equation is used to simulate ow of river, ow of liquid in an open channel, tsunami etc. The Kurganov-Petrova (KP) scheme which was developed based on the local speed of discontinuity ...
    • Tuning PD and PID Controllers for Double Integrating Plus Time Delay Systems 

      Ruscio, David Luigi Di; Dalen, Christer (Journal article; Peer reviewed, 2017)
      An existing method for tuning a PI controller for an integrating plus time delay plant are extended to be used for the design of a PD controller for a double integrating plus time delay plant. The PD controller is extended ...